From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: DRI Development <dri-devel@lists.freedesktop.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
Julia Lawall <julia.lawall@lip6.fr>
Subject: [PATCH] drm/sysfs: Grab lock for edid/modes_show
Date: Fri, 2 Oct 2015 10:39:31 +0200 [thread overview]
Message-ID: <1443775171-31600-1-git-send-email-daniel.vetter@ffwll.ch> (raw)
In-Reply-To: <1443513993-5228-2-git-send-email-daniel.vetter@ffwll.ch>
We chase pointers/lists without taking the locks protecting them,
which isn't that good.
Fix it.
v2: Actually unlock properly, spotted by Julia.
Cc: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
drivers/gpu/drm/drm_sysfs.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
index 7506de0a75b4..9bffa63fe849 100644
--- a/drivers/gpu/drm/drm_sysfs.c
+++ b/drivers/gpu/drm/drm_sysfs.c
@@ -261,23 +261,29 @@ static ssize_t edid_show(struct file *filp, struct kobject *kobj,
struct drm_connector *connector = to_drm_connector(connector_dev);
unsigned char *edid;
size_t size;
+ ssize_t ret = 0;
+ mutex_lock(&connector->dev->mode_config.mutex);
if (!connector->edid_blob_ptr)
- return 0;
+ goto unlock;
edid = connector->edid_blob_ptr->data;
size = connector->edid_blob_ptr->length;
if (!edid)
- return 0;
+ goto unlock;
if (off >= size)
- return 0;
+ goto unlock;
if (off + count > size)
count = size - off;
memcpy(buf, edid + off, count);
- return count;
+ ret = count;
+ mutex_unlock(&connector->dev->mode_config.mutex);
+unlock:
+
+ return ret;
}
static ssize_t modes_show(struct device *device,
@@ -288,10 +294,12 @@ static ssize_t modes_show(struct device *device,
struct drm_display_mode *mode;
int written = 0;
+ mutex_lock(&connector->dev->mode_config.mutex);
list_for_each_entry(mode, &connector->modes, head) {
written += snprintf(buf + written, PAGE_SIZE - written, "%s\n",
mode->name);
}
+ mutex_unlock(&connector->dev->mode_config.mutex);
return written;
}
--
2.5.1
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next prev parent reply other threads:[~2015-10-02 8:39 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-29 7:37 [PATCH] drm: Fix locking for sysfs dpms file Daniel Vetter
2015-09-29 7:56 ` Daniel Vetter
2015-09-29 13:30 ` Jani Nikula
2015-09-29 14:37 ` Jens Axboe
2015-09-29 8:06 ` [PATCH 1/3] drm/sysfs: Annote lockless show functions with READ_ONCE Daniel Vetter
2015-09-29 8:06 ` [PATCH 2/3] drm/sysfs: Grab lock for edid/modes_show Daniel Vetter
2015-10-02 8:39 ` Daniel Vetter [this message]
2015-10-02 11:01 ` [PATCH] " Daniel Vetter
2015-10-02 12:08 ` Emil Velikov
2015-11-19 16:22 ` Daniel Vetter
2015-10-02 15:02 ` Julia Lawall
2015-09-29 8:06 ` [PATCH 3/3] drm/sysfs: Nuke TV/DVI property files Daniel Vetter
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